* test/ruby/test_thread.rb (invoke_rec): extend timeout 10 -> 50 sec,
  to investigate test failure on rubyci.
  http://a.mrkn.jp/~mrkn/chkbuild/mountain_lion/ruby-2.0.0-m64-o0/log/20130507T052909Z.log.html.gz


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40600 b2dd03c8-39d4-4d8f-98ff-823fe69b080e